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Growth Hormone Replacement Pregnancy: Not recommended during pregnancy and in women of childbearing potential not using contraception — animal studies are insufficient and no clinical studies on exposed pregnancies are available. Breast-feeding: no clinical studies conducted; it is not known whether somatropin is excreted in human milk, but absorption of intact protein from the infant's gastrointestinal tract is extremely unlikely — caution should be exercised.

Somatropin (Recombinant Human Growth Hormone)

Brand names: Genotropin, Humatrope, Norditropin, Saizen, Omnitrope

Somatropin is recombinant human growth hormone used to treat growth hormone deficiency and several other approved conditions affecting growth and body composition in children and adults.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Growth hormone deficient adults: in adult-onset GHD start with a low dose of 0.15 to 0.3 mg per day; in patients continuing growth hormone therapy after childhood-onset GHD the recommended dose to restart is 0.2 to 0.5 mg per day. Increase the dose gradually according to individual patient requirements as determined by the IGF-I concentration
Route: Subcutaneous injection — vary the injection site to prevent lipoatrophy
Frequency: Once daily
Max: The maintenance dose seldom exceeds 1.0 mg per day (and seldom exceeds 0.5 mg per day in patients above 60 years). The maximum recommended daily dose should not be exceeded
PRODUCT-SPECIFIC: this draft is from the UK SPC for Genotropin 12 mg powder and solvent for solution for injection. Somatropin dosing differs between brands and presentations — confirm the exact product before prescribing. The dosage and administration schedule should be individualised. Treatment goal is IGF-I concentrations within 2 SDS of the age-corrected mean; patients with normal IGF-I at the start should be titrated up to the upper range of normal, not exceeding 2 SDS. Clinical response and side effects may also guide titration; some patients with GHD do not normalise IGF-I despite a good clinical response and do not require dose escalation. Women may require higher doses than men, particularly those on oral oestrogen replacement (risk of under-treatment); dose accuracy should be checked every 6 months. Patients above 60 years: start at 0.1 to 0.2 mg per day and increase slowly; use the minimum effective dose. Where childhood-onset GHD persists into adolescence, treatment should be continued to achieve full somatic development. US labelling (Norditropin) gives a different adult regimen — non-weight-based: initiate at approximately 0.2 mg/day (range 0.15 to 0.3 mg/day), increasing every 1-2 months by approximately 0.1 to 0.2 mg/day; or weight-based (not recommended for obese patients): initiate at 0.004 mg/kg daily, increasing to a maximum of 0.016 mg/kg daily. SOURCE GAP: section 4.5 (interactions) was not captured in the fetched bundle.

Paediatric dose

Dose: 0.025 mg/kg
Route: Subcutaneous injection — vary the injection site to prevent lipoatrophy
Frequency: Once daily (dose expressed per day)
Max: Prader-Willi syndrome: daily doses of 2.7 mg should not be exceeded
UK SPC (Genotropin) paediatric dosage by indication, per day: growth hormone deficiency in children 0.025 to 0.035 mg/kg/day (or 0.7 to 1.0 mg/m2/day) — even higher doses have been used; Prader-Willi syndrome 0.035 mg/kg/day (1.0 mg/m2/day), not exceeding 2.7 mg/day and not to be used in children with a growth velocity of less than 1 cm per year or near closure of the epiphyses; Turner syndrome 0.045 to 0.050 mg/kg/day (1.4 mg/m2/day); growth disturbance in chronic renal insufficiency 0.045 to 0.050 mg/kg/day (1.4 mg/m2/day) — higher doses may be needed if growth velocity is too low, and a dose correction may be needed after six months; short children born small for gestational age 0.035 mg/kg/day (1 mg/m2/day) usually until final height is reached, discontinuing after the first year if height velocity SDS is below +1, and discontinuing if height velocity is under 2 cm/year (bone age over 14 years in girls or over 16 years in boys). The dosePerKg value above is the lower bound of the GHD range — use the indication-specific figure. Contraindicated for growth promotion in children with closed epiphyses. Verify against a children's formulary before use.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

UK SPC (Genotropin) paediatric dosage by indication, per day: growth hormone deficiency in children 0.025 to 0.035 mg/kg/day (or 0.7 to 1.0 mg/m2/day) — even higher doses have been used; Prader-Willi syndrome 0.035 mg/kg/day (1.0 mg/m2/day), not exceeding 2.7 mg/day and not to be used in children with a growth velocity of less than 1 cm per year or near closure of the epiphyses; Turner syndrome 0.045 to 0.050 mg/kg/day (1.4 mg/m2/day); growth disturbance in chronic renal insufficiency 0.045 to 0.050 mg/kg/day (1.4 mg/m2/day) — higher doses may be needed if growth velocity is too low, and a dose correction may be needed after six months; short children born small for gestational age 0.035 mg/kg/day (1 mg/m2/day) usually until final height is reached, discontinuing after the first year if height velocity SDS is below +1, and discontinuing if height velocity is under 2 cm/year (bone age over 14 years in girls or over 16 years in boys). The dosePerKg value above is the lower bound of the GHD range — use the indication-specific figure. Contraindicated for growth promotion in children with closed epiphyses. Verify against a children's formulary before use.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients
  • Any evidence of activity of a tumour — intracranial tumours must be inactive and antitumour therapy completed before starting growth hormone; discontinue if there is evidence of tumour growth
  • Growth promotion in children with closed epiphyses
  • Acute critical illness with complications following open heart surgery, abdominal surgery, multiple accidental trauma, acute respiratory failure or similar conditions

Side effects

  • Adults: fluid retention effects — peripheral oedema, face oedema, musculoskeletal stiffness, arthralgia, myalgia and paraesthesia (common; generally mild to moderate, arising in the first months and subsiding spontaneously or with dose reduction)
  • Adults: carpal tunnel syndrome (uncommon)
  • Children: injection-site reaction (common); arthralgia, myalgia, musculoskeletal stiffness, peripheral oedema (uncommon)
  • Headache (adults and children, uncommon); benign intracranial hypertension (uncommon in children, rare in adults)
  • Type 2 diabetes mellitus (uncommon); blood cortisol decreased
  • Rash, pruritus, urticaria (uncommon in children, rare in adults); gynaecomastia; antibody formation in approximately 1% of patients (low binding capacity, no associated clinical changes)

Interactions

  • Insulin — somatropin may reduce insulin sensitivity; the insulin dose may require adjustment after somatropin is instituted, and patients with diabetes, glucose intolerance or additional diabetes risk factors should be monitored closely
  • Glucocorticoid replacement therapy — somatropin may inhibit 11-beta-HSD-1 and reduce serum cortisol, unmasking central hypoadrenalism; patients on glucocorticoid replacement may require an increase in maintenance or stress doses
  • Oral oestrogen therapy — if started, the somatropin dose may need to be increased to maintain IGF-1 in the normal age-appropriate range; if oral oestrogen is discontinued, the somatropin dose may need to be reduced
  • Thyroid hormones — growth hormone increases extrathyroidal conversion of T4 to T3; monitor thyroid function in all patients (hypothyroidism may develop in subclinical hypothyroidism)
  • Note: section 4.5 was not captured in the fetched bundle — the above are drawn from sections 4.2 and 4.4. The US label additionally states that pharmacologic and supraphysiologic glucocorticoid treatment may attenuate the growth-promoting effect in paediatric patients

Clinical monograph

How it works

It replaces endogenous growth hormone, binding growth hormone receptors to stimulate linear growth, protein synthesis and lipolysis, with many effects mediated through IGF-1.

Prescribing in practice

  • Somatropin is contraindicated in active malignancy and in acutely critically ill patients, and should not be used where there is evidence of active tumour.
  • It can impair glucose tolerance and unmask diabetes, and may reduce cortisol and thyroxine levels, so other pituitary axes and glucose should be assessed and replaced as needed.
  • In children, benign intracranial hypertension and slipped capital femoral epiphysis have been reported, so new headaches, visual changes or hip or knee pain should be evaluated.

Monitoring

Monitor growth and IGF-1, together with glucose, thyroid and adrenal function and, in children, the spine and visual symptoms, throughout treatment.

Counselling the patient

  • Rotate injection sites and store the product as directed to maintain stability.
  • Report persistent headaches, vision changes, or hip or knee pain in children.
  • Report increased thirst or urination, which may indicate effects on blood sugar.

Evidence & guidelines

Somatropin is a long-established replacement therapy whose indications and safety profile are detailed in the SPC and reflected in relevant NICE technology appraisals.

Reference: NICE TA64 (Somatropin for Adult GH Deficiency); NICE TA188 (Paediatric GH Deficiency); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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